The inventions described herein may be manufactured, used and licensed by or for the U.S. Government for U.S. Government purposes.
1. Field of the Invention
The present invention relates to case telescoped ammunition and, more particularly, large caliber case telescoped ammunition, i.e., of a caliber on the order of 105 mm or larger.
2. Background of the Invention
Case telescoped ammunition, or CTA, is a term used for ammunition wherein the projectile is telescoped back into, or contained completely within, the cartridge case. Such ammunition differs from most conventional ammunition wherein the front end of the projectile protrudes from the front of the cartridge case.
At present, case telescoped ammunition has been developed for 40 mm, 75 mm and 90 mm cartridges, which are generally considered to be small and medium caliber cartridges. This ammunition is designed for maximum pressures of approximately 70 Kpsi.
As far as the inventors are aware, there is currently no 105 mm or larger caliber case telescoped ammunition. One problem with developing such large caliber ammunition is that the pressures are larger (up to 90 Kpsi) and this presents special challenges as described in more detail below. There is a specific demand for 105 mm CTA for use in a rapid autoloader swing chamber gun being developed for the U.S. Future Combat System (FCS) Multi-Role Armament Ammunition System (MRAAS).
According to the invention, case telescoped ammunition is provided which is of larger caliber than the corresponding ammunition of the prior art and which is suitable for use in, inter alia, the swing chamber gun mentioned above.
In accordance with the invention, there is provided a case telescoped ammunition cartridge comprising:
a cartridge case having a forward end and an aft end;
a projectile disposed within the casing and having a forward end and an aft end;
a sleeve surrounding at least a portion of the forward end of the projectile and having a forward end and an aft end;
an obturator disposed between the aft end of the sleeve and a part of said portion of the forward end of the projectile;
an aft end seal affixed to said case at the aft end of case so as to be relatively movable with respect thereto during firing of the cartridge and including an external lateral surface adapted to engage an inner wall surface of a gun chamber; and
a forward end seal affixed to said case at the forward end of the case so as to be relatively movable with respect thereto during firing of the cartridge and including an external lateral surface adapted to engage the inner wall surface of the gun chamber and an external end surface adapted to abut a forward end surface of the gun chamber, said forward seal being secured to the forward end of said sleeve so as to support said sleeve within the case.
Preferably, the forward and aft end seals are cup-shaped and include a base portion and a substantially cylindrical wall portion projecting outwardly from the base portion. Advantageously, the wall portions of the end seals include engagement surfaces for engaging corresponding engagement surfaces of the cartridge case. The engagement surfaces of the end seals and the cartridge case preferably include V-shaped grooves therein for enabling longitudinal dislocation between the end seals and the corresponding ends of the cartridge case while preventing full disengagement of said engagement surfaces and corresponding separation of said end seals from said case. The engagement surfaces of said end seals are advantageously located on interior parts of the projecting wall portions thereof. Preferably, the projecting wall portion of the forward end seal further includes an interior surface secured to said sleeve and located forwardly of the engagement surface of the forward end seal. Advantageously, this interior surface includes screw threading and a corresponding portion of the sleeve secured to the forward end seal includes complementary screw threading.
In one preferred embodiment, the external lateral surfaces of the end seals include a non-metal coating thereon. The coating advantageously comprises a plastic or rubber coating.
In an alternative preferred embodiment, the end seals include at least one ring member extending around the external lateral surfaces thereof. Advantageously, the ring member comprises a rubber or plastic member.
Further features and advantages of the present invention will be set forth in, or apparent from, the detailed description of preferred embodiments thereof which follows.